Information processing device and display brightness control method

Abstract

An information processing device comprises a display unit whose display brightness is changeable, a unit for detecting the lightness of surroundings, a unit for determining a target display brightness of the display unit responsive to the lightness detected by the unit for detecting the lightness, and a unit for changing the display brightness of the display unit in steps until the target display brightness is reached when changing the display brightness to the target display brightness determined by the unit for determining the target display brightness.

1. An information processing device comprising:
 a display unit having changeable display brightness; 
 a detector configured to detect a lightness of surroundings; 
 a calculating unit configured to calculate a target display brightness of the display unit based on the surrounding lightness detected by the detector; 
 a selector configured to select a first mode when the difference between the target display brightness and the current display brightness is larger than a predetermined threshold brightness and a second mode when the difference between the target display brightness and the current display brightness is not larger than the predetermined threshold brightness; and 
 a brightness control unit configured to supply a brightness control signal for changing a current display brightness to the display unit when the current display brightness does not equal the target display brightness, 
 wherein, when the first mode is selected, the brightness control unit supplies a first brightness control signal changing the current display brightness by a predetermined brightness which is smaller than a difference between the current display brightness and the target brightness, and 
 when the second mode is selected, the brightness control unit supplies a second brightness control signal changing the current display brightness by the difference. 
 
   
   
     2. The information processing device according to  claim 1 , further comprising an input unit configured to input a selection one of the first mode and the second mode upon a user operation. 
   
   
     3. The information processing device according to  claim 1 , wherein the predetermined brightness is obtained by dividing a brightness range of the changeable display brightness with a predetermined number. 
   
   
     4. The information processing device according to  claim 1 , wherein the predetermined threshold brightness is variable. 
   
   
     5. A method of controlling brightness of an information processing device having a display unit with changeable display brightness, the method comprising:
 detecting a lightness of surroundings; 
 calculating a target display brightness of the display unit based on the detected surrounding lightness; 
 selecting a first mode when the difference between the target display brightness and the current display brightness is larger than a predetermined threshold brightness and a second mode when the difference between the target display brightness and the current display brightness is not larger than the predetermined threshold brightness; and 
 supplying a brightness control signal for changing a current display brightness to the display unit when the current display brightness does not equal the target display brightness, 
 wherein, when the first mode is selected, supplying a first brightness control signal changing the current display brightness by a predetermined brightness which is smaller than a difference between the current display brightness and the target brightness, and 
 when the second mode is selected, supplying a second brightness control signal changing the current display brightness by the difference. 
 
   
   
     6. The method according to  claim 5 , further comprising enabling user input of the selecting of the first mode and the second mode. 
   
   
     7. The information processing device according to  claim 5 , further comprising setting the display brightness of the display unit to a first brightness level when a first lightness level is detected and to a second brightness level when a second lightness level is detected, and
 changing from the first brightness level to a third brightness level which is between the first brightness level and the second brightness level and then from the third brightness level to the second brightness level when the display brightness is changed from the first brightness level to the second brightness level. 
 
   
   
     8. The information processing device according to  claim 7 , further comprising changing from the first brightness level to the third brightness level and then from the third brightness level to the second brightness level after a lapse of a predetermined time period. 
   
   
     9. The method according to  claim 5 , wherein the predetermined brightness is obtained by dividing a brightness range of the changeable display brightness with a predetermined number. 
   
   
     10. The method according to  claim 5 , wherein the predetermined threshold brightness is variable.